This invention relates to valves, and more particularly to a throttle valve for supplying combustion air or fuel-air mixture to an intake associated with an engine.
It is known to control the supply of fuel-air mixture to an engine intake by positioning a throttle valve between the engine and a mixer. The throttle valve defines a flow passage positioned between the mixer outlet and the engine intake inlet, and a valve member in the form of a butterfly or spool member is disposed within the flow passage. The position of the valve member controls the flow of fuel-air mixture supply through the flow passage to the engine intake. The valve member is coupled to the output shaft of an electromagnetic variable reluctance actuation device which functions to control the position of the valve member within the valve passage in response to input signals supplied to the electromagnetic actuation device. In the case of a fuel injected engine, the throttle valve controls the supply of combustion air to the engine intake.
A prior art throttle valve construction involves separate housings for the valve arrangement and the electromagnetic actuation device. In this construction, a valve subassembly is first constructed by rotatably mounting the butterfly or spool member within the flow passage defined by the valve housing, resulting in a valve subassembly. An electromagnetic actuation device such as a force motor assembly, which includes a sensor arrangement, is then mounted to a motor housing, resulting in a motor subassembly. The valve subassembly and the motor subassembly are then assembled together, which results in coupling the force motor output shaft with the butterfly or spool member, to provide a motor-driven valve assembly.
While the above-described valve construction and assembly is generally satisfactory, it involves creation of two separate subassemblies which are then are assembled together. Each subassembly contemplates a number of components and assembly steps, and an overall assembly step is required to provide the final valve assembly. This requires an alignment between the subassemblies and a coupling arrangement which complicates assembly of the valve.
It is the object of the present invention to reduce the overall parts requirement and number of assembly steps for producing a throttle valve assembly. It is a further object of the invention to provide a throttle valve assembly which is relatively simple in its components and assembly, yet which provides highly satisfactory operation and accurate positioning of the valve member within the flow passage. Yet another objection of the invention is to provide a throttle valve assembly in which the force motor and the sensor assembly are mounted to the valve body separately from each other. A still further object of the invention is to eliminate the requirement in the prior art to assemble the motor output shaft to a shaft carrying the butterfly or spool member.
In accordance with one aspect of the invention, a throttle valve assembly for supplying air or fuel-air mixture to an intake associated with an engine includes an integrally formed valve body adapted for mounting to the engine. The valve body defines an actuation device cavity, a flow passage adapted to communicate with the engine intake, and an opening extending between the flow passage and the actuation device cavity. The throttle valve assembly further includes a valve shaft including a first portion disposed within the flow passage and a second portion disposed within the actuation device cavity, and the valve shaft extends through the opening defined by the valve body. A valve member is mounted to the first portion of the valve shaft and is disposed within the flow passage for controlling the flow of air or fuel-air mixture therethrough. An electromagnetic actuation device is received within the actuation device cavity, and a contactless coupling arrangement is interposed between the second portion of the valve shaft and the electromagnetic actuation device for controlling the position of the valve shaft, and thereby the valve member, in response to operation of the electromagnetic actuation device.
In accordance with another aspect of the invention, a throttle valve assembly includes an integral valve body including a flow passage, an actuation device cavity, a sensor mounting structure, a first opening communicating between the flow passage and the actuation device cavity, and a second opening communicating between the flow passage and the location adjacent the sensor mounting structure. An electromagnetic actuation device is mounted within the actuation device cavity, and a shaft member extends transversely through the flow passage. The shaft member defines a first portion extending through the first opening and the second portion extending through the second opening, and the shaft member is rotatably supported relative to the valve body within the first and second openings. A valve member is mounted to the shaft member and disposed within the flow passage. A contactless coupling arrangement is interconnected with the first end of the shaft member for imparting rotation to the shaft member in response to operation of the electromagnetic actuation device. A position indicating member is interconnected with the second portion of the shaft member. A positioning sensing arrangement is mounted to the sensor mounting structure defined by the valve body for sensing the position of the shaft, and thereby the valve member, in response to orientation of the position indicating member relative to the position sensing arrangement. The valve body preferably defines opposed first and second ends, and the flow passage is formed so as to extend transversely through the valve body between the first and second ends. The actuation device cavity opens onto the first end of the valve body, and the sensor mounting structure is formed on the second end of the valve body.
In accordance with another aspect of the invention, an electromagnetic actuation device for imparting rotation to a valve shaft in a throttle valve assembly includes a coil housing having a solid central core and an annular coil recess surrounding the core and opening onto an end defined by the coil housing. The coil housing further defines an outer wall located outwardly of the coil recess. A coil is received within the coil recess, and a pole carrier is interconnected with the valve shaft. A pole arrangement is mounted to the pole carrier, and is oriented relative to the coil housing such that the coil arrangement extends into the coil recess inwardly of the end defined by the coil housing.
In accordance with yet another aspect of the invention, a drive arrangement for a throttle valve assembly includes an actuation device cavity formed in the valve body and a coil-type electromagnetic actuation device received within the actuation device cavity and interconnected with the valve body. The electromagnetic actuation device includes a coil housing defining an annular coil recess. A recess is formed in the valve body and extends from an inner end defined by the actuator device cavity. An output member, preferably in the form of an output shaft, is interconnected with the valve arrangement and rotatably mounted to the valve body. A pole carrier is disposed within the recess formed in the valve body, and is interconnected with the output member. A pole arrangement is interconnected with the pole carrier and extends into the coil recess for selectively imparting rotation to the pole carrier, and thereby to the output member, in response to energization of the coil. The output member is preferably in the form of a valve shaft to which the valve arrangement is mounted, and the pole carrier is preferably carried by the valve shaft. With this construction, the pole arrangement is carried by the valve shaft itself, which eliminates the need for coupling the valve shaft to the motor output shaft as in the prior art.
In accordance with yet another aspect of the invention, a stop arrangement for a throttle valve assembly includes stop structure defined by the valve body. The stop structure includes at least one shoulder, and a stop member is interconnected with the valve arrangement and oriented relative to the valve body so as to engage the shoulder when the valve arrangement attains a predetermined position relative to the valve body and the flow passage. Engagement of the stop member with the shoulder functions to prevent movement of the valve arrangement relative to the valve body when the valve arrangement attains a predetermined position relative to the valve body. In a preferred form, the stop structure includes a pair of spaced shoulders, and the stop member engages the shoulders to define the range of movement of the valve arrangement relative to the valve body.
In accordance with yet another aspect of the invention, a position sensing arrangement for a throttle valve assembly includes an extension member interconnected with the valve arrangement and a position indicating member carried by the extension member. A position sensing arrangement is secured to the valve body, and is operable to sense the position of the valve arrangement in response to orientation of the position indicating member relative to the position sensing arrangement. In this manner, the position sensing arrangement is operable to sense the position of the valve arrangement relative to the valve body. In a preferred form, stop structure is preferably formed on the valve body adjacent the location at which the position sensing arrangement is mounted to the valve body, so as to simplify assembly of the stop arrangement and the position sensing arrangement to the valve body and to remove the stop arrangement and the position sensing arrangement from the location at which the electromagnetic actuation device is mounted to the valve body.
In accordance with yet another aspect of the invention, a valve arrangement for a throttle valve assembly defines a flow passage and includes a valve shaft adapted for rotatable mounting to the valve body and a drive arrangement interconnected with the valve shaft for selectively imparting rotation to the valve shaft. A valve member is adapted for placement within the flow passage. The valve member is preferably in the form of a pair of wings extending laterally from an axially extending offset central mounting portion adapted to be secured to the valve shaft. This construction provides a simplified arrangement for forming a butterfly valve assembly and for mounting the butterfly valve assembly to the valve body.
In accordance with a still further aspect of the invention, a method of making a throttle valve includes providing a one-piece integrally formed valve body which defines a transverse flow passage in combination with an actuation device cavity. A first opening is formed in the valve body and extends between the motor cavity and the flow passage. A second opening is provided on the valve body on an opposite side of the flow passage from the first opening. The method contemplates inserting a valve shaft into the flow passage such that a first portion of the valve shaft is rotatably received within the first opening, and a second portion of the valve shaft is rotatably received within the second opening. A valve member is secured to the valve shaft within the flow passage, and an electromagnetic actuation device is then mounted within the actuation device cavity. The first portion of the valve shaft is drivingly coupled with the electromagnetic actuation device, preferably in a contactless manner, such that operation of the electromagnetic actuation device functions to control the position of the valve member within the flow passage.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.